:root {
    /*--background-color: #2c3e50;*/
    --show_color1: #03a9f4;
    --show_color2: #f441a5;
}

* {
    margin: 0;
    padding: 0;
}
h1 {
    color:white;
}
body {
    width: 100vw;
    height: 100vh;
    background-color: var(--background-color);
    display: flex;
    justify-content: center;
    align-items: center;
}
div{
    color:white
}
.bt {
    font-size: 30px;
    color: #FFF;
    background: linear-gradient(90deg, var(--show_color1), var(--show_color2));
    padding: 24px 48px;
    border-radius: 60px;
    position: relative;
    overflow: hidden;
}

.bt span{
    position: absolute;
    background-color: #FFF;
    border-radius: 50%;
    transform: translate(-50%,-50%);
    animation: show 1s;
}

@keyframes show{
    0%{
        opacity: 0.5;
        width: 0;
        height: 0;
    }
    100%{
        opacity: 0;
        width: 300px;
        height: 300px;
    }
}
input::input-placeholder{
       color : white;
}
input::-webkit-input-placeholder{
       color : white;
}
input::-moz-placeholder{
       color : white;
}
input:-moz-placeholder{
        color : white;
}
input:-ms-input-placeholder{
        color : white
}

.demo{
                position:fixed;
                top: 0;
                left: 0;
                width:100%;
                height:100%;
                min-width: 1000px;
                z-index:-10;
                zoom: 1;
                background-color: #fff;
                background: url(bkg.jpg);
                background-repeat: no-repeat;
                background-size: cover;
                -webkit-background-size: cover;
                -o-background-size: cover;
                background-position: center 0;
}